Electromagnetic pump

ABSTRACT

The present invention includes an electromagnetically responsive pump including a spring-biased piston assembly reciprocatory within a cylinder. Inlet and outlet fittings formed with inlet and outlet ports, respectively, are secured to opposite ends of the cylinder. An electromagnetic coil surrounds a portion of the cylinder and, when energized, is operative to move the piston assembly against its spring bias. The piston assembly is formed with a fluid-conducting slot which communicates with said outlet port. Sealing means for sealing said slot from the inlet port comprise a sealing ring engaging inner walls of the cylinder, and flanges forming part of said piston assembly spaced from and disposed on opposite sides of the sealing ring, said flanges movably engaging first and second portions of the sealing ring during suction and return strokes of the piston assembly, said slot being sealed from the inlet port during the suction stroke and communicating therewith during the return stroke. A springbiased check valve normally seals the inlet port.

Morton A. Kmitchman South Orange, NJ. App]. No. 849,067 [22] Filed Aug. 11,1969 [45] Patented Aug. 24, 1971 Assignee Vnlcor Engineering Corporation Kenllworth, NJ.

ELECTROMAGNETIC PUMP 8 Claims, 5 Drawing Figs.

Inventor United States Patent ELECTROMAGNETIC PUMP This invention relates to pumps and more specifically to an electromagnetic oscillating-armature piston-type pump.

It is an object of the present invention to provide a pump which is compact, efficient, quiet in operation, relatively inexpensive to manufacture, simple to assemble, repair and service and capable of being made in a variety of sizes and capacities.

Another object of this invention is to provide a pump of the electromagnetic oscillating-armature piston type in which a floating sealing ring disposed between a piston assembly and 'a cylinder within which the piston assembly reciprocates, serves both as a check valving member as well as a piston ring.

A further object is to provide a pump structure as above which is capable of use as a vacuum pump.

Still another object of this invention is to provide a pump in which one of the pumping elements includes a piston made of magnetizable material which serves as the armatureof a solenoid actuator, the piston including portions which cooperate with the above floating sealing ring.

The invention will be more clearly understood from the following description of a specific embodiment of the invention together with the accompanying drawing, in which;

FIG. 1 is a sectional elevational view of a pump according to the present invention;

FIG. 2 is a fragmentary sectional elevational view of a check valve in an open position and adjacent structure of the pump shown in FIG. 1;

F IG. 3 is a fragmentary sectional elevational view of the check valve of FIG. 2 shown in a closed position;

FIG. 4 is a sectional elevational view of a pump according to this invention in which a flexible disc is utilized;

F 16.5 is a sectional elevational view of the pump of FIG. 4 illustrating the inlet sealed.

Referring now in more detail to the drawing, a pump according to the present invention is shown in FIG. 1 as including a housing 11 which is made up of a cylindrical sleeve 12 which extends between end plates 13 and 14. Plates 13 and 14 are centrally apertured to permit the extension of a cylinder assembly 15 therethrough.

An electromagnetic coil 16 is mounted within sleeve 12 and surrounds a stepped-diameter cylinder 17. Cylinder 17 extends between an inlet end within which an inlet fitting member 18 is secured as described below, and an outlet end within which an outlet fitting member 19 is secured.

Inlet fitting 18 is formed with a central bore 20 which is of a stepped diameter such that a shoulder 21 forming a bearing surface results from a larger diameter at inlet end 22 and a smaller diameter through the central portion of fitting 18. This inlet fitting is further formed with external threads 23 which are matingly engaged by the internal threads of a cover member 24 which is threaded against shoulder 25 of fitting 18 when in an assembled position. A palnut 26 engages threads 23 to maintain cover member 24 against shoulder 25 as shown in FIG. 1. Fitting 18 is further formed with a successively tapered outer surface 27 which is shaped to frictionally retain an inlet supply conduit shown .in phantom outline and designated as reference character 28.

lnlet'fitting 18 is further formed with an annular bearing surfacewhich forms the valve seat 29 of a check valve 30. Check valve 30 includes a valve poppet 31 which is formed with a groove 32 within which an O-ring 33 is situated. A helical coil spring 34 is secured at one of its ends to poppet 31 and extends through bore 20 to a retaining member 35 which is maintained against shoulder 21 as a result of tension within spring 34. As shown in FIG. 1, valve poppet 31 is biased toward a closed position against valve seat 29 as a result of tension within helical spring 34. Retaining member 35 is shaped so as to permit the flow of fluid therethrough from inlet end 22 of fitting 18 into bore 20.

Fitting 18 is maintained within cylinder 17 in the assembled position shown in FIG. 1 by means of a slotted oval-headed bolt 36 which extends through end plates 13 and 14 of housing shown as being hexagonal, although it is within the scope of the present invention to provide any shape. Nuts 39 and 40 secure bolt 36 to cover member 24. While one bolt 36 is shown in FIG. 1, of course a plurality of bolts is contemplated as being included in this invention. 1

Inlet fitting 18 in its assembled position is located such that shoulder 25 thereof is substantially flush with the end of cylinder 17. A larger diameter portion 41 of fitting 18 is located internally of cylinder 17 and is formed with an annular groove 42 within which an O-type searing ring 43 is situated. Searing ring 43 is in a compressed state between the walls defining groove 42 and the internal walls of cylinder 17, thereby forming a fluid-type seal between the interior of cylinder 17 and the environment.

Looking now in more detail at outlet fitting 19, this fitting is formed with a counterbore 46 which extends therethrough between outlet end 44 of the fitting and a chamber 45 defined by cylinder 17. A reduced diameter portion 47 of fitting l9 provides a bearing surface against which end portions 48 of cylinder 17 may be swaged, thereby holding fitting 19 and cylinder 17 in an integral relationship with one another. Relative axial movement between fitting 19 and cylinder 17 is prevented by means of a radially extending flange 49 which defines the termination point of reduced diameter portion 47 in one direction, and a larger diameter portion 50 of fitting 19 in the opposite direction.

A radially extending flange 51 provides the means against which end plate 13 bears, thereby aligning and locating fitting 19 in the coaxial position with respect to cylinder 17 shown in FIG. 1. Fitting 19 is further formed with a groove 52 within which a resilient ring 53 is positioned, the diameter of ring 53 being greater than the depth of groove 52 such that the ring extends from fitting 19 into chamber 43 in a predetermined amount. Ring 53 comprises a bumper or shock absorbing and noise preventing means against which a piston assembly 54, described in detail below, strikes during operation of pump 10.

Fitting 19 includes outer surfaces 55 similar to surface 27 which frictionally retain an outlet conduit 56 shown in phantom.

Piston assembly 54 includes an elongated generally cylindrical piston member 57 which is formed with a central bore 58 as well as a radially extending slot 59 which communicates with bore 58. Piston member 57 is normally spring biased downwardly as shown in FIG. 1 due to the presence of a helical compression spring 60 which extends from one end thereof which is located at the bottom of central bore 58 to its opposite end which engages face portions 61 of fitting 19 immediately surrounding counterbore 46. Piston member 57 is formed from a magnetizable material of low magnetic reluctance.

Piston member 54 is formed with a pair of radially extending flanges 62 and 63 which define an annular groove 64, groove 64 being in communication with slot 59, central bore 58 and chamber 45.

The outside diameters of flanges 62 and 63 are slightly less than the inside diameter of cylinder 17 within which flanges 62 and 63 are located. As such, an annular space exists between these flanges and the inner wall of cylinder 17, through which fluid may pass.

An O-type sealing ring 65 in sealing contact with the inner wall of cylinder 17 is located partially within groove 64 and between flanges 62 and 63. The width or diameter of sealing ring 65 is sufficiently smaller than the width of groove 64, i.e., the distance between flanges 62 and 63, such that fluid may pass between sealing ring 65 and a flange which is not in contact with the sealing ring.

Movement of piston assembly 54. within cylinder 17 during an energized or power stroke is accomplished by the supply of electricity to electromagnetic coil 16 via an insulated conductor or cord 66. Cord 66 is secured to end plate 13 by means of a grommet 67, which acts as a strain relief. The energizing of electromagnetic coil 16 causes coil 16 and piston assembly 54 to act as a solenoid wherein piston assembly 54 acts as the armature. Upon coil 16 being energized, piston assembly 54 is drawn toward the center of coil 16 against the compressive forces of helical spring 60. Upon the deenergization of electromagnetic coil 16, the compressive forces within spring 60 urge piston assembly 54 off center and toward the inlet port. By intermittent energizing of coil 16, an oscillatory movement of piston assembly 54 within cylinder 17 results, the energized movement of the piston assembly comprising both positive seal pumping and suction strokes, which results in pumping the fluid from the inlet port to the outlet port and simultaneously creating suction intake at the inlet port.

During the power stroke or movement of piston assembly 54 toward the center of electromagnetic coil 16 as a result of the energization of coil 16, flange 63 will engage sealing ring 65 in the position shown in FIG. 2. The relative positions of sealing ring 65 and flange 63 during this movement of the piston assembly toward the coil during the power stroke are maintained. Movement of piston assembly 54 away from the center of electromagnetic coil 16 as a result of forces exerted by helical spring 60 comprises the return or deenergized stroke.

During the power stroke, sealing ring 65 acts both (1) as a piston ring in that a seal is maintained against the inner wall of cylinder 17, and (2) as check valve means in that a fluid-type seal is maintained between a chamber 68 within which check valve poppet 31 is situated, and groove 64.

During the return stroke of piston assembly 54, on the other hand, it is flange 62 which engages sealing ring 65. During this return stroke, fluid is free to pass from chamber 68 past the space between flange 63 and cylinder 17, thereafter into groove 64 and thence through slot 59 and bore 58 into chamber 45. It should be apparent that this fluid within chamber 45 is displaced and caused to pass through counterbore 46 and out through outlet end 44 into conduit 56 as a result of upward movement of piston assembly 54.

In operation, pump starts its pumping functioning upon the intermittent supplying of current to electromagnetic coil 16 via conductor 66, thereby periodically energizing the coil and causing piston assembly 54 to move toward the center of coil 16 in a power stroke during this energization. Compression spring 60 is compressed during this power stroke.

Due to the substantially fluidtight seal maintained by O-ring 65 between flange 63 of piston assembly 54 and the wall of cylinder 17 during the power stroke, as well as the seal maintained by O-ring 43 between fitting l8 and the cylinder, a pressure drop in chamber 68 occurs. The pressure in chamber 68 drops to a predetermined point whereby the tension force in spring 34 is overcome and poppet 31 of check valve 30 is unseated (see FIG. 2) thereby permitting fluid to flow from conduit 28 through bore 20 and into chamber 68. Depending upon the spring rate of spring 34, check valve 30 will close (see FIG. 3) either immediately prior to the end of the suction stroke of piston assembly 54 or at the end of this stroke itself. Pistonassembly 54 strikes rubber ring 53 at the end of the power stroke, ring 53 absorbing the shock and preventing noise and wear between the piston assembly and the outlet fitting.

Upon deenergization of coil 16, spring 60 forces piston assembly 54 to move in a return stroke in the direction shown in FIG. 3, with the result that fluid which has been described as having entered chamber 68 is displaced past flange 63 and O- ring 65, through slot 59 and bore 58 and thereafter into chamber 45. Upon the next successive power stroke of the piston assembly, this same fluid which occupies chamber 45 is positively displaced through bore 46 and out of pump 10 into outlet conduit 56.

FIGS. 4 and 5 illustrate an alternative preferred embodiment of this invention in which a flexible disc 70 functionally replaces the floating O-ring 65 already described for FIGS.

1-3. A piston member 71, much like piston member 57, differs structurally in that it is formed with internal threads 72 at its lowermost end in place of flanges 62 and 63. A support plate 73 which is contoured in a predetermined shape to accommodate flexible disc 70, sandwiches disc 70 against piston member 71 such that the outer periphery of disc 70 engages the inner walls of cylinder 17 as shown in FIG. 4. The interference between disc 70 and the walls of cylinder 17 may be varied by varying the size of the disc as well as the contour of support 73. A headed bolt 74 matingly engages threads 72, thereby holding the disc and support plate in place.

Disc 70 performs effectively the same function as O-ring 65. During energization of the coil, piston member 71 moves in a power stroke such that disc 70, supported by plate 73, acts as a positive seal and pumps fluid through the outlet. Simultaneously during this power stroke, a suction is created at the inlet port.

Upon deenergization of the coil, piston member 71 moves downwardly toward the inlet and, due to the inherent flexibility of disc 70, bypass action occurs such that fluid passes between plate 73 and the cylinder. Trapped fluid below disc 70 enters the void created by this plunger-type motion.

The embodiment of the invention particularly disclosed is presented merely as an example of the invention. Other embodiments, forms and modifications of the invention coming within the proper scope of the appended claims will, of course, readily suggest themselves to those skilled in the art.

What is claimed is:

l. A pump comprising:

a. a housing defining an internal pumping chamber and having inlet and outlet ports communicating with said chamber;

b. a piston moveable in first and second directions within said chamber and having a fluid conducting opening extending between portions of said chamber proximal to said outlet port and other portions of said chamber;

c. a sealing member connected to said piston to engage the inner walls of said chamber during movement of said piston in said first direction;

d. means connected to said piston for supporting said sealing member when said piston moves in said first direction, said means having a contoured lateral surface adjacent said member to deflect said member substantially in conformity with the shape of said surface;

e. means for biasing said piston in said second direction; and

f. electromagnetic means for moving said piston in said first direction.

2. The pump as recited in claim 1, wherein said sealing member comprises a flexible disc concentric with said piston and having a diameter greater than the diameter of said pumping chamber.

3. The pump as recited in claim 1, wherein said sealing member comprises a flexible annular blade concentric with said piston and having a diameter greater than the diameter of said pumping chamber.

4. The pump as recited in claim 1 wherein said sealing member comprises a peripheral portion pivotally arranged relative to said piston such that pressure exerted on said portion when said piston moves in said first direction tends to pivot said portion against the inner walls of said chamber.

5. The pump as recited in claim 4, wherein said contoured surface comprises an annular shelf inclined substantially in said first direction and engageable with the proximal lateral surface of said portion when said piston moves in said first direction.

6. The pump as recited in claim 1, wherein said piston comprises a substantially cylindrical member having a central bore which opens at one end of said member proximal to said outlet port, said bore communicating substantially along its entire length with said fluid conducting opening.

7. The pump as recited in claim 6, wherein said fluid conducting opening extends substantially radially between said bore and said pumping chamber.

bears against a portion of the in chamber adjacent said outlet p0 ner boundary of said pumping n. 

1. A pump comprising: a. a housing defining an internal pumping chamber and having inlet and outlet ports communicating with said chamber; b. a piston moveable in first and second directions within said chamber and having a fluid conducting opening extending between portions of said chamber proximal to said outlet port and other portions of said chamber; c. a seAling member connected to said piston to engage the inner walls of said chamber during movement of said piston in said first direction; d. means connected to said piston for supporting said sealing member when said piston moves in said first direction, said means having a contoured lateral surface adjacent said member to deflect said member substantially in conformity with the shape of said surface; e. means for biasing said piston in said second direction; and f. electromagnetic means for moving said piston in said first direction.
 2. The pump as recited in claim 1, wherein said sealing member comprises a flexible disc concentric with said piston and having a diameter greater than the diameter of said pumping chamber.
 3. The pump as recited in claim 1, wherein said sealing member comprises a flexible annular blade concentric with said piston and having a diameter greater than the diameter of said pumping chamber.
 4. The pump as recited in claim 1 wherein said sealing member comprises a peripheral portion pivotally arranged relative to said piston such that pressure exerted on said portion when said piston moves in said first direction tends to pivot said portion against the inner walls of said chamber.
 5. The pump as recited in claim 4, wherein said contoured surface comprises an annular shelf inclined substantially in said first direction and engageable with the proximal lateral surface of said portion when said piston moves in said first direction.
 6. The pump as recited in claim 1, wherein said piston comprises a substantially cylindrical member having a central bore which opens at one end of said member proximal to said outlet port, said bore communicating substantially along its entire length with said fluid conducting opening.
 7. The pump as recited in claim 6, wherein said fluid conducting opening extends substantially radially between said bore and said pumping chamber.
 8. The pump as recited in claim 1, wherein said biasing means comprises a helical compression spring, one end of which is disposed within said bore and the other end of which bears against a portion of the inner boundary of said pumping chamber adjacent said outlet port. 